.banner {
    width: 400px;
    height: 100px;
    margin: 50px auto;
    position: relative;
    background: #ccc;
    overflow: hidden;
}

.imgbox a {
    position: absolute;
    width: 400px;
    height: 100px;
    left: 400px;
    top: 0;
}

.imgbox a img {
    width: 400px;
    height: 100px;
}

.btns > * {
    position: absolute;
    width: 20px;
    height: 20px;
    background: rgba(200, 200, 200, 0.7);
    text-align: center;
    line-height: 20px;
    top: 40px;
}

.btns .left {
    left: 0
}

.btns .right {
    right: 0
}

.list {
    position: absolute;
    bottom: 0;
    background: rgba(200, 200, 200, 0.7);
    display: flex;
    left: 0;
    right: 0;
    text-align: center;
    line-height: 20px;
    height: 20px;
}

.list span {
    flex: 1;
    border-left: solid 1px #fff;
    border-right: solid 1px #fff;
}

.list span.active {
    background: red;
    color: #fff
}